Help with learning Kanji

So a quick question.

In most of the Onyomi and Kunyomi for Kanji I see a few letters or characters (not exactly sure what I should refer to such as) and then a red dot and then another few.

み ・ み.つ ・ みっ.つ
Here's an example. Are these all different ways you can pronounce the same kanji? or the entire pronunciation spaced out?